The present invention relates to an apparatus and a process of assembly in the form of a thermally fused or glued one-piece cartridge for the production of ultrapure water.
Ultrapure water, with resistivity greater than 18 megohms-cm and with a total organic compound (TOC) level less than 20 parts per billion, is obtained from slightly ionized water by four or five successive treatments comprising filtration, contact with activated charcoal, contact with mixed anionic and cationic resins, optionally contact with a mixture of resins and activated charcoal, and, lastly a microfiltration step.
The water treatment elements utilized to conduct these treatment steps are traditionally assembled separately in the form of cartridges (very low pressure tubes with tips) incorporated within casings which are often difficult to disassemble, despite the mandatory frequent changing of the cartridges. Moreover, the internal volume, excluding the treatment elements, e.g., the volume between the cartridge and the casing is large, and a relatively long recirculation time is required before water of the desired quality is obtained.